Implant for immobilizing cervical vertebrae

ABSTRACT

A spinal implant for immobilizing the C1 vertebra with respect to the C2 vertebra of the spine provides controlled coupling between the C1 and C2 vertebrae, and includes a C1 component attachable to the C1 vertebra, two C2 components attachable to the C2 vertebra, and a transverse element. The C1 component has two wings each of which retains a rod holder that rotates and translates for capturing a C2 component rod. Each C2 component has a hook for connection with a side of the C2 vertebra lamina and a rod for attachment to one of the rod holders of the C1 component. Each C2 component receives and secures the transverse connector which holds position of the C2 components relative to one another. Each C2 component may include a plate configured for compression against the C2 vertebra spinous process, with each plate including spikes to aid in preventing construct migration.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 14/596,849filed on Jan. 14, 2015, which claims the benefit of and/or priorityunder 35 U.S.C. §119(e) to U.S. Application No. 61/927,095 filed on Jan.14, 2014 and titled “Implant For Immobilizing Cervical Vertebrae”; theentire contents of all of which are incorporated herein by reference.

FIELD OF INVENTION

The present disclosure relates to devices for immobilizing vertebrae ofthe spine and, more particularly, to devices for immobilizing the C1vertebra with respect to the C2 vertebra of the spine.

BACKGROUND

Because of various circumstances such as injury, trauma, degeneration orthe like, it becomes necessary to immobilize one or more vertebrae withrespect to other vertebrae of the spine. This includes vertebrae of thelumbar, thoracic and the cervical areas. Various devices have beendevised in order to accomplish this result.

While these devices are adequate to immobilize lumbar vertebrae,thoracic vertebrae, and some of the cervical vertebrae of the spine,they are particularly deficient in effectively immobilizing the C1cervical vertebra relative to the C2 cervical vertebra. The C1 or atlasvertebra is the topmost cervical vertebra of the human spine and, alongwith the C2 or axis vertebra forms the joint connecting the skull andspine. A major difference of the atlas cervical vertebra relative toother vertebrae is that it does not have a body but is fused with the C2vertebra. The C2 vertebra forms the pivot upon which C1 rotates. It isbecause of these peculiarities that prior art vertebral immobilizationdevices are inadequate for use with a C1 to C2 immobilization.

In view of the above, it can be appreciated that it would be desirableto have a better device, method and manner of immobilizing the C1vertebra to the C2 vertebra.

The present invention sufficiently accomplishes these means.

SUMMARY OF THE INVENTION

The present invention is a spinal implant for immobilizing the C1vertebra with respect to the C2 vertebra of the spine. Theimmobilization implant provides controlled coupling between the C1 andC2 vertebrae.

The immobilization implant includes a C1 component configured forattachment to the C1 vertebra, two C2 components each configured forattachment to the C2 vertebra, and a transverse element.

The C1 component can have a singular hook configured for placementmidline on the C1 vertebra or multiple hooks configured for placement onmultiple areas of the C1 vertebra. The arms and/or hook(s) are capableof being bent and translated to a desired position. The C1 component hastwo arms that each retains a rod holder which is configured to rotateand translate with respect to its respective arm for capturing a rodfrom each C2 component. This allows the device to accommodate varyinganatomy.

In one form, the rod holder of each arm is retained in a slot in theupper surface of the respective arm. This allows each rod holder totranslate along the respective arm in the cephalad-caudal direction.Rotation of each rod holder is fixed through interaction betweenstructures on the bottom outside surface of the rod holder andstructures beneath the bottom outside surface of the rod holder withinthe slot. In a particular instance, and without being limiting, suchstructures may be serrations, teeth or the like. Downward pressureexerted on the rod holder causes the two structures to mesh and lock.Other manners of fixing rotation of the rod holder may be used.

In another form, the rod holder of each arm is retained in a slot in theside surface of the respective arm. This allows each rod holder totranslate along the respective side arm in the cephalad-caudaldirection. Rotation of each rod holder is fixed through interactionbetween structures on the lower outside surface of the rod holder andstructures adjacent the lower outside surface of the rod holder withinthe slot. In a particular instance, and without being limiting, suchstructures may be serrations, teeth or the like. Downward pressureexerted on the rod holder causes the two structures to mesh and lock.Other manners of fixing rotation of the rod holder may be used.

The underside of the C1 hook may be configured to provide stablesecuring of the C1 hook at its implanted position after the surgeonreleases the implant instrumentation therefrom. This feature may beembodied as spring-loaded serrated teeth that projects from the C1 hook.The serrated teeth are angled and thus retained within the hook suchthat the serrated teeth recess into the hook during insertion andpositioning of the C1 hook on the lamina of (or other relevant anatomy)at the particular level (e.g. C1), then is biased against the lamina of(or other relevant anatomy) by its spring-loading to help keep the hookin the same position at which it was intended.

Each C2 component has a body with a hook for connection with a side ofthe C2 vertebra lamina and a rod for attachment to one of the rodholders of the C1 component. Each C2 component is also configured toreceive and secure the transverse connector or element that holds aposition of the C2 components relative to one another. The transverseelement runs caudally to the C2 spinous process. In one form, the bodyof each C2 component is integrated with a plate that is configured to becompressed against the C2 vertebra spinous process. Each plate includesprojecting spikes to aid in preventing migration of the construct onceinstalled.

In one form, the transverse element may include integrated connectorsconfigured to connect the C1/C2 construct (the present spinal implant)to an occipital rod that connects the occiput to the cervical/thoracicregion.

The present spinal implant may also be used with respect to theimmobilization of vertebrae other than the C1/C2 vertebrae such as theother cervical vertebrae, the thoracic vertebrae, and the lumbarvertebrae.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features of this invention, and the mannerof attaining them, will become apparent and the invention itself will bebetter understood by reference to the following description ofembodiments of the invention taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a view of a device for immobilizing a C1 vertebra of the spinerelative to a C2 vertebra of the spine fashioned in accordance with theprinciples of the present invention;

FIG. 2 is a view of one of two C2 components of the cervical vertebraeimmobilization device of FIG. 1;

FIG. 3 is another view of the C2 component of FIG. 2;

FIG. 4 is a view of a C1 component of the cervical vertebraeimmobilization device of FIG. 1;

FIG. 5 is an enlarged partial view of the C1 component of FIG. 4;

FIG. 6 is another view of the C1 component of FIG. 4;

FIG. 7 is another view of the C1 component of FIG. 4;

FIG. 8 is a view of the cervical vertebrae immobilization device of FIG.1 installed on the C1 and C2 vertebrae of the spine;

FIG. 9 is another view of the cervical vertebrae immobilization deviceof FIG. 1 installed on the C1 and C2 vertebrae of the spine;

FIG. 10 is a view of the cervical vertebrae immobilization device ofFIG. 1 installed on the C1 and C2 vertebrae of the spine and having anadditional transverse element thereon for connecting the cervicalimmobilization device to an occipital rod;

FIG. 11 is a view of another cervical vertebrae immobilization devicefashioned in accordance with the principles of the present invention;

FIG. 12 is an underside view of the cervical vertebrae immobilizationdevice of FIG. 11;

FIG. 13 is an end view of the cervical vertebrae immobilization deviceof FIG. 11;

FIG. 14 is another view of the cervical vertebrae immobilization deviceof FIG. 11;

FIG. 15 is a top view of the cervical vertebrae immobilization device ofFIG. 11; and

FIG. 16 is an end view of the cervical vertebrae immobilization deviceof FIG. 11.

Although the drawings represent embodiments of various features andcomponents according to the present invention, the drawings are notnecessarily to scale and certain features may be enhanced in order tobetter illustrate and explain the present invention. Theexemplifications set out herein thus illustrate embodiments of theinvention, and such exemplifications are not to be construed as limitingthe scope of the invention in any manner.

DETAILED DESCRIPTION

Those of skill in the art will understand that various details of theinvention may be changed without departing from the spirit and scope ofthe invention. Furthermore, the foregoing description is forillustration only, and not for the purpose of limitation.

Referring to the figures and in particular, FIG. 1, there is depicted anexemplary embodiment of an implant or device, generally designated 10,for immobilizing vertebrae of the spine and particularly, but notnecessarily, the cervical vertebrae of the spine and, more particularly,but not necessarily, a C1 (atlas) vertebra of the spine relative to a C2(axis) vertebra of the spine fashioned in accordance with the presentprinciples. Thus, while the present vertebral immobilization implant 10is shown and described herein with respect to the C1 and C2 vertebrae ofthe spine, it should be appreciated that the vertebral immobilizationimplant 10 may be used with other vertebrae of the spine. Additionally,as described further below, the vertebral immobilization implant 10allows connection to other vertebral implants if desired.

As seen in FIG. 1, in general, the vertebral immobilization implant 10has a C1 component 12 configured to attach to the C1 vertebra, and twoC2 components 14 a, 14 b each one configured to attach to the C2vertebra. Particularly, the C1 component 12 is attached to the posteriorarch of the C1 vertebra, while each C2 component 14 a, 14 b attaches tothe vertebral body of C2 on opposite sides of its spinous process (see,e.g. FIGS. 8-10). A transverse element or connector, shown in the formof a rod 70, is provided between and captured by the two C2 components14 a, 14 b. The transverse element 70 allows the position of the C2components to be fixed relative to one another and to aid in securingeach C2 component by compression to respective sides of the C2 spinousprocess.

FIG. 4 shows the C1 component 12. The C1 component 12 is made from abiocompatible material such as, but not limited to, stainless steel ortitanium. The C1 component 12 is defined by a body 16 having first andsecond arms, wings, extensions or the like (arms) 20 a, 20 b thatproject from a generally central head 18, the nomenclature first andsecond being arbitrary here and throughout unless otherwise indicated.Each arm 20 a, 20 b is generally paddle or ovoid-shaped but may takedifferent forms if desired. A channel, groove, concavity, depression orthe like 21 separates the first and second arms 20 a, 20 b. As depictedin FIG. 4, each arm 20 a, 20 b project outwardly and generally downward.Each arm however, may be angled as desired relative to the head 18. Thisis particularly illustrated in the position of the arms 20 a, 20 b inFIGS. 6 and 7. Angling the arms 20 a, 20 b provides a better fit on theC1 vertebra.

Referring back to FIG. 4, the first arm 20 a includes a recess, cutoutor the like (recess) 22 a that extends in and along an upper surface ofthe arm 20 a. A first holder 24 a is positioned within the recess 22 a.The first holder 24 a is rotatable within the recess 22 a and thusrelative to the arm 20 a. The rotational position of the first holder 24a is fixed through interaction of the bottom area of the first holder 24a with a first fixation structure 23 a within the recess 22 a. The firstfixation structure 23 a is illustrated as a first ring of teeth,notches, serrations or the like (teeth) with the bottom area of thefirst holder 24 a configured with a like ring of teeth. The first holder24 a may also translate within the recess 22 a.

The first holder 24 a is generally U-shaped and thus defines a slotbetween first and second cupped sides 25 a, 27 a. The slot of the firstholder 24 a is configured to receive a bar or rod 44 a of the C2component 14 a. The first side 25 a has threading 28 a on the insidecupped surface thereof, with the second side 27 a also having threading26 a on the inside surface thereof. The internal threading 26 a, 28 a isconfigured to receive a threaded set screw 90 for securing the bar 44 aof the C2 component.

The second arm 20 b includes a recess, cutout or the like (recess) 22 bthat extends in and along an upper surface of the arm 20 b. A secondholder 24 b is positioned within the recess 22 b. The second holder 24 bis rotatable within the recess 22 b and thus relative to the arm 20 b.The rotational position of the second holder 24 b is fixed throughinteraction of the bottom area of the second holder 24 b with a secondfixation structure 23 b within the recess 22 b. The second fixationstructure 23 b is illustrated as a second ring of teeth, notches,serrations or the like (teeth) with the bottom area of the second holder24 b configured with a like ring of teeth. The second holder 24 b mayalso translate within the recess 22 b.

The second holder 24 b is generally U-shaped and thus defines a slotbetween first and second cupped sides 25 b, 27 b. The slot of the secondholder 24 b is configured to receive a bar or rod 44 b of the C2component 14 b. The first side 25 b has threading 28 b on the insidecupped surface thereof, with the second side 27 b also having threading26 b on the inside surface thereof. The internal threading 26 b, 28 b isconfigured to receive a threaded set screw 90 for securing the bar 44 bof the C2 component.

As seen in FIGS. 4 and 5, the C1 component 12 has a hook structure 29extending from the underside of the head 18. The hook 29 has a generallyplanar tongue 30 that defines a recess 31. The hook 29 is configured toattach to and around the posterior arch of the C1 vertebra and,particularly, the posterior arch of the C1 vertebra is received in therecess 31 of the hook 29 with the tongue extending under the C1posterior arch, and more particularly midline on the C1 vertebra. Thehook 29 is configured to be bent at various angles to accommodatevarying C1 anatomy.

The underside of the hook 29 is configured to provide stable securementof the hook 29 at its implanted position after it is released from theimplant instrumentation. While not being limiting, in one form, thisfeature is embodied as spring-loaded serrated teeth 33 that projectsfrom a recess 32 on the underside of the hook 29. The serrated teeth 33are angled and thus retained within the recess 32 such that the serratedteeth 33 recede into the head 18 during insertion and positioning of thehook 29 on the lamina of the C1 vertebra. The teeth 33 are then biasedagainst the lamina of by its spring-loading in order to help keep thehook in the same position at which it was intended.

FIGS. 2 and 3 particularly show the first C2 component 14 a. The secondC2 component 14 b is a mirror image of the first C2 component. As suchthe second C2 component will not be discussed in detail since itsfeatures, components and configuration are the same as the first C2component, the numerical labeling of which ends in a “b”. The first C2component 14 a has a body 40 a that defines a plate 42 a having anangled front face 58 a and an angled rear face 62 a, the nomenclaturefront and rear being arbitrary. The front face 58 a is generally planar.The rear face 62 a is generally planar with a plurality of spikes,projections or the like (spikes) 63 a extending outwardly therefrom. Therear face 68 a is angled to follow the contour or angling of a side ofthe spinous process SP (see, e.g., FIGS. 8-10). The spikes 63 a areconfigured to grip the side of the spinous process SP. A bore 59 aextends through the plate 42 a from the front face 58 a to the rear face68 a. The bore 59 a accepts a bone screw or other fastener (not shown)in order to positively secure the plate 42 a to the side of the spinousprocess SP if desired.

The body 40 a further has a rod, shaft, pole or the like (rod) 44 a thatprojects outwardly from a side 45 a of the plate 42 a. The rod 44 a isconfigured to be received in the first holder 24 a of the C1 component(see, e.g., FIGS. 8-10). The rod 44 a also has a length that allows thefirst holder 24 a of the C1 component to receive and retain the rod 44 aat various longitudinal positions along the rod, thereby providinglength adjustment between the C1 component/C1 vertebra and the first C2component/C2 vertebra and/or a side of the spinous process SP. Thisaccommodates variations in anatomy (i.e. spacing between the C1 vertebraand the C2 vertebra).

The body 40 a moreover has a rod holder 50 a that extends from an end ofthe plate 42 a opposite the end 45 a and offset from a longitudinal axisof the rod 44 a. The rod holder 50 a has a front portion 54 a thatextends outward from and generally perpendicular to the side of theplate 42 a. The front portion 54 a has threading 55 a on an insidesurface. The rod holder 50 a further includes a rear portion 52 a thatextends from the bottom of the front portion 54 a such that the rodholder 50 a is generally cupped shaped and defines a rod holder areatherein and between the front and rear portions 54 a, 52 a. The rearportion 52 a has threading 53 a on an inside surface facing thethreading 55 a of the front portion 54 a. The threading 53 a, 55 a isconfigured to receive a set screw 90 or the like (see, e.g., FIGS.8-10).

A hook 46 a extends from a bottom of the rod holder 50 a and defines ahook area 47 a. The hook 46 a is configured to attach onto and extendunder a portion of the lamina of the C2 vertebra adjacent one side(first side) of the spinous process SP thereof (see, e.g. FIGS. 8-10).Particularly, as discerned in FIGS. 8-10, the first C2 component 14 a isdesigned to hook or grasp onto and/or around the inferior end of the C2lamina.

As indicated above, the second C2 component 14 b is a mirrorconfiguration of the C1 component 14 a. Thus, while the first C2component 14 a is configured to connect to the left side of the C2vertebra and extend to the left side of the C1 vertebra, the second C2component 14 b is configured to connect to the right side of the C2vertebra and extend to the right side of the C1 vertebra. The rod 44 aof the first C2 component 14 a is received in the rod holder 24 a of theC1 component 12 while the rod 44 b of the second C2 component 14 b isreceived in the rod holder 24 b of the C1 component.

FIGS. 8 and 9 particularly show various views of the present vertebralimmobilization implant 10 situated, implanted on, or otherwise attachedto and between the C1 vertebra and the C2 vertebra. The vertebralimmobilization implant 10 stabilizes the C1 and C2 vertebrae relative toone another.

FIG. 10 shows a variation of the present implant 10 wherein thetransverse element 70 has been replace with a transverse elementassembly 80 for connecting the present implant 10 to one or moreoccipital rods that connect the occiput to the cervical/thoracic regionof the spine. The transverse element assembly 80 includes a rod 81 thatis configured to be received in the first and second rod holders 50 a,50 b of the respective first and second C2 components 14 a, 14 b. Afirst rod holder (integrated connector) 82 a is provided on a first endof the rod 81 and is configured to receive a connecting rod (not shown).A second rod holder (integrated connector) 82 b is provided on a secondend of the rod 81 and is configured to receive another connecting rod(not shown). The rod holders 82 a, 82 b are configured to each receive athreaded set screw 90. Other configurations and/or manners of providingthis connection are contemplated.

Referring to FIGS. 11-16, there is shown another exemplary embodiment ofan implant or device, generally designated 100, for immobilizingvertebrae of the spine in like manner and function and to the implant10. In general, the vertebral immobilization implant 100 has a C1component 112 configured to attach to the C1 vertebra, and two C2components 114 a, 114 b each one configured to attach to the C2vertebra. Particularly, the C1 component is attached to the posteriorarch of the C1 vertebra, while each C2 component 114 a, 114 b attachesto the vertebral body of C2, preferably, but not necessarily, onopposite sides of its spinous process (see, e.g. FIGS. 8-10). Atransverse element or connector, shown in the form of a rod 170, isprovided between and captured by the two C2 components 114 a, 114 b. Thetransverse element 170 allows the position of the C2 components 114 a,114 b to be fixed relative to one another and to aid in securing each C2component by compression to respective sides of the C2 spinous process.

The C1 component 112 is made from a biocompatible material such as, butnot limited to, stainless steel or titanium. The C1 component 112 isdefined by a body 116 having first and second arms, wings, extensions orthe like (arms) 117 a, 117 b, the nomenclature first and second beingarbitrary here and throughout unless otherwise indicated. Each arm 117a, 117 b is generally paddle or ovoid-shaped but may take differentforms if desired. A lower notch 118 a is formed at the bottom of thebody 116 between the first and second arms 117 a, 117 b. A first uppernotch is formed at the top of the body 116 adjacent the first arm 117 a,while a second upper notch is formed at the top of the body 116 adjacentthe second arm 117 b. Each arm 117 a, 117 b project outwardly andgenerally downward. Each arm however, may be angled as desired relativeto the head 18.

As best seen in FIG. 11, the first arm 117 a includes a slot or the like119 a that extends in and along the side of the first arm 117 a. A firstadjustable element 120 a is retained in the slot 119 a so as to betranslatable (movable) along the length of the slot 119 a (in themedial-lateral direction or transverse plane) and rotatable relativethereto. As such, the first adjustable element 120 a is rotatablerelative to the first arm 117 a. A weld plate 140 a ensures that a hook121 a of the first adjustable element 120 a does not disassociate fromthe body 116/arm 117 a. The weld plate 120 a also ensures that thetranslation of the first adjustable element remains parallel with themedial-lateral (transverse) plane and does not travel obliquely.

The first adjustable element 120 a includes a generally U-shaped rodholder 121 a defining a slot between two cupped sides, the slotconfigured to receive the rod (134 a, 134 b) of a C2 component (114 a,114 b). While not seen, the two cupped sides have threading on theinside cupped surface thereof. The internal threading is configured toreceive a threaded set screw 90 for securing the rod of the C2component.

The first adjustable element 120 a also includes a hook 122 a extendingfrom the underside of the rod holder 121 a. The hook 122 a defines apocket or reception area 123 a configured to attach to and around aportion of the posterior arch of the C1 vertebra. The hook 122 a may beconfigured to be bent at various angles to accommodate varying C1vertebra anatomy.

Again, as best seen in FIG. 11, the second arm 117 b includes a slot orthe like 119 b that extends in and along the side of the second arm 117b. A second adjustable element 120 b is retained in the slot 119 b so asto be translatable (movable) along the length of the slot 119 b (in themedial-lateral direction or transverse plane) and rotatable relativethereto. As such, the second adjustable element 120 b is rotatablerelative to the second arm 117 b. A weld plate 140 b ensures that a hook121 b of the second adjustable element 120 b does not disassociate fromthe body 116/arm 117 b. The weld plate 120 b also ensures that thetranslation of the first adjustable element remains parallel with themedial-lateral (transverse) plane and does not travel obliquely.

The second adjustable element 120 b includes a generally U-shaped rodholder 121 b defining a slot between two cupped sides, the slotconfigured to receive the rod (134 a, 134 b) of a C2 component (114 a,114 b). While not seen, the two cupped sides have threading on theinside cupped surface thereof. The internal threading is configured toreceive a threaded set screw 90 for securing the rod of a C2 component.

The second adjustable element 120 b also includes a hook 122 b extendingfrom the underside of the rod holder 121 b. The hook 122 b defines apocket or reception area 123 b configured to attach to and around aportion of the posterior arch of the C1 vertebra. The hook 122 b may beconfigured to be bent at various angles to accommodate varying C1vertebra anatomy.

The C2 component 114 a will now be described. The second C2 component114 b is a mirror image of the first C2 component 114 a. As such thesecond C2 component 114 b will not be discussed in detail since itsfeatures, components and configuration are the same as the first C2component, and its numerical labeling of which ends in a “b”. The firstC2 component 114 a has a body 130 a having a rod, shaft, pole or thelike (rod) 134 a that projects outwardly from an end of the body 130 a.The rod 134 a is configured to be received in the rod holder 121 a ofthe C1 component. The rod 134 a also has a length that allows the rodholder 121 a of the C1 component to receive and retain the rod 134 a atvarious longitudinal positions along the rod, thereby providing lengthadjustment between the C1 component/C1 vertebra and the first C2component/C2 vertebra. This accommodates variations in anatomy (i.e.spacing between the C1 vertebra and the C2 vertebra).

The body 130 a moreover has a rod holder 131 a that is formed at an endof the body 130 a opposite the rod 134 a. The rod holder 131 a utilizesan end wall of the body 130 a as one side of the two sided rod holder131 a and a shaped flange as the other side. The outside surface of theend wall and the inside surface of the shaped flange both have threadingfor receiving the threaded set screw 90. A hook 132 a extends from abottom of the rod holder 131 a and defines a hook area 133 a (see, e.g.,FIG. 12). The hook 131 a is configured to attach onto and extend under aportion of the lamina of the C2 vertebra adjacent one side of itsspinous process SP. This is in like manner to the first C2 component 14a shown in FIGS. 8-10 wherein the first C2 component 14 a is designed tohook or grasp onto and/or around the inferior end of the C2 lamina.

As indicated above, the second C2 component 114 b is a mirrorconfiguration of the C1 component 114 a. Thus, while the first C2component 114 a is configured to connect to the left side of the C2vertebra and extend to the left side of the C1 vertebra, the second C2component 114 b is configured to connect to the right side of the C2vertebra and extend to the right side of the C1 vertebra. The rod 44 aof the first C2 component 114 a is received in the rod holder 24 a ofthe C1 component 12 while the rod 44 b of the second C2 component 114 bis received in the rod holder 24 b of the C1 component.

The implant 100 is attached to the spine in a manner similar if not thesame as the implant 10. As such, reference should be made to FIGS. 8-10that show various views of the vertebral immobilization implant 10situated, implanted on, or otherwise attached to and between the C1vertebra and the C2 vertebra. The vertebral immobilization implant 100stabilizes the C1 and C2 vertebrae relative to one another.

While the invention has been illustrated and described in detail in theforegoing drawings and description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly illustrative embodiments thereof have been show and described andthat all changes and modifications that are within the scope of thefollowing claims are desired to be protected.

All references cited in this specification are incorporated herein byreference to the extent that they supplement, explain, provide abackground for or teach methodology or techniques employed herein.

What is claimed is:
 1. An implant for immobilizing a first bone relative to a second bone, the implant comprising: a first component comprising: a body including a first arm and a second arm; a first adjustable element operatively coupled to the first arm to translate laterally along and rotationally relative to the first arm, the first adjustable element including a rod holder and a hook configured to engage the first bone; a second adjustable element operatively coupled to the second arm to translate laterally along and rotationally relative to the second arm, the second adjustable element including a rod holder and a hook configured to engage the first bone; a second component comprising: a rod holder; a hook extending from the rod holder and configured to engage the second bone; a rod extending from the rod holder to be received in the rod holder of the first adjustable element of the first component; a third component comprising: a rod holder; a hook extending from the rod holder and configured to engage the second bone; a rod extending from the rod holder to be received in the rod holder of the second adjustable element of the first component; a transverse rod received in and extending between the rod holder of the second component and the rod holder of the third component in order to fix position of the second and third components relative to one another.
 2. The implant of claim 1, wherein the first arm includes a first slot, the second arm includes a second slot, the first adjustable element includes a first projection that engages and moves within the first slot, and the second adjustable element includes a second projection that engages and moves within the second slot.
 3. The implant of claim 1, wherein the body includes a first notch in a first edge of the body, a second notch in a second edge of the body opposite the first edge, and a third notch in the second edge spaced apart from the second notch.
 4. The implant of claim 1, wherein the first component further comprises a first plate coupled to the first arm and a second plate coupled to the second arm, the first and second arms configured to limit motion of the respective first and second adjustable elements.
 5. The implant of claim 1, wherein the first and second arms of the body of the first component angle anteriorly from respective first and second sides of the body.
 6. The implant of claim 5, wherein the hook on each of the first and second adjustable elements extends from the respective rod holder.
 7. The implant of claim 1, wherein the transverse rod is retained in the rod holder of the second component by a first rod holder setscrew, and in the rod holder of the third component by a second rod holder setscrew.
 8. A method of immobilizing a first bone relative to a second bone with an implant having a first component, a second component, and a transverse rod; wherein the first component comprises a body including a first arm and a second arm; a first adjustable element coupled to the first arm to translate laterally along and rotationally relative to the first arm, the first adjustable element including a rod holder and a hook to engage the first bone; and a second adjustable element coupled to the second arm to translate laterally along and rotationally relative to the second arm, the second adjustable element including a rod holder and a hook to engage the first bone; wherein the second component comprises a rod holder; a hook extending from the rod holder to engage the second bone; and a rod extending from the rod holder to be received in the rod holder of the first adjustable element of the first component; wherein the third component comprises a rod holder; a hook extending from the rod holder to engage the second bone; and a rod extending from the rod holder to be received in the rod holder of the second adjustable element of the first component; wherein the transverse rod engages the rod holders of the second and third components to fix position of the second and third components relative to one another; wherein the method comprising the steps of: surgically installing the implant onto and between the first vertebra and the second vertebra of the spine.
 9. The method of claim 8, wherein the step of providing the implant includes providing a plurality of projections extending from the body to engage the second vertebra, and wherein the body of the third component includes a plurality of projections extending from the body to engage the second vertebra.
 10. A spinal implant for immobilizing a first vertebra of a spine with respect to a second vertebra of the spine, the spinal implant comprising: a body including a first arm and a second arm; a first adjustable element coupled to the first arm to translate laterally along and rotationally relative to the first arm, the first adjustable element including a rod holder and a hook configured to engage the first bone; a second adjustable element coupled to the second arm to translate laterally along and rotationally relative to the second arm, the second adjustable element including a rod holder and a hook configured to engage the first bone; a first component comprising a rod holder, a hook extending from the rod holder and configured to engage the second bone, and a first post extending from the rod holder and received in the rod holder of the first adjustable element; a third component comprising a rod holder, a hook extending from the rod holder and configured to engage the second bone, a second post extending from the rod holder and received in the rod holder of the second adjustable element; a rod coupled to the rod holder of the second component and the rod holder of the third component to fix position of the second and third components relative to one another.
 11. The spinal implant of claim 10, wherein the first and second wings of the body angle anteriorly from a mid-point of the body.
 12. The spinal implant of claim 10, wherein: the rod comprises a cylindrical shape; the first post comprises a cylindrical shape; the second post comprises a cylindrical shape.
 13. The spinal implant of claim 10, wherein the first arm includes a first slot, the second arm includes a second slot, the first adjustable element includes a first projection that moves within the first slot, and the second adjustable element includes a second projection that moves within the second slot.
 14. The spinal implant of claim 13, wherein the first component further comprises a first plate coupled to the first arm proximate the first slot and a second plate coupled to the second arm proximate the second slot, the first and second arms configured to limit motion of the respective first and second adjustable elements.
 15. The spinal implant of claim 10, wherein the body includes a first notch in a first edge of the body, a second notch in a second edge of the body opposite the first edge, and a third notch in the second edge spaced apart from the second notch.
 16. The spinal implant of claim 10, wherein the first and second arms of the body of the first component angle anteriorly from respective first and second sides of the body.
 17. The spinal implant of claim 10, wherein the hook on each of the first and second adjustable elements extends from the respective rod holder.
 18. The spinal implant of claim 10, wherein the rod is retained in the rod holder of the second component by a first rod holder setscrew, and in the rod holder of the third component by a second rod holder setscrew. 